Anti-angiogenic activity of heparin-like polysulfonated polymeric drugs in 3D human cell culture.

The activity of new anti-angiogenic polymeric drugs was tested in a 3D endothelial cell culture system applied as a model of angiogenesis. The assay was performed in a highly reproducible fibrin matrix that supported endothelial cell attachment, proliferation, migration, and formation of capillary-like structures. Active growth factors (FGF and/or VEGF) were added to the medium to induce the formation of blood vessel-like structures, and the effect of the active polymers was then tested by a semi-quantitative immunostaining protocol and visualized by laser-scanning confocal microscopy. The synthetic heparin-like macromolecules that were tested for their anti-angiogenic efficacy were previously characterized in terms of their anti-proliferative activity in 2D tissue culture. Two different anti-angiogenic monomers, a methacrylic derivative of 5-amino-2-naphthalenesulfonic acid (MANSA) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS), were copolymerized with a hydrophilic monomer (vinyl pyrrolidone, VP) or a hydrophobic monomer (butyl acrylate, BA), giving rise to different copolymeric systems with controlled microstructure and supramolecular organization. Both copolymeric systems have demonstrated a composition-dependent anti-mitogenic effect in "2D in vitro" cell culture experiments using aFGF as pro-angiogenic growth factor and BALB/c 3T3 fibroblast as cell model, as was shown in a previous publication. These 3D experiments provide evidence for the strong and specific modulation of angiogenesis by these systems. The 3D experiments constitute an improvement over 2D in vitro experiments and in vivo experiments with angiogenic drugs and may help to reduce the number of animal experiments.